In recent years, there have been various endeavors to use nonaqueous electrolyte secondary batteries in, for example, electric vehicles, hybrid cars, and the like. In such applications, it is necessary to ensure safety in cases where, if the nonaqueous electrolyte secondary battery is subjected to impact, excessive heat may be generated in the interior and the electrolyte may break down, with the result that the interior pressure rises. Therefore, JP-A-2011-18645 proposes the provision of a pressure-sensitive forced short-circuiting mechanism in nonaqueous electrolyte secondary batteries.
In a nonaqueous electrolyte secondary battery, the pressure inside the container increases due to deterioration. Therefore, when there is a prolonged use period, the forced short-circuiting mechanism may activate erroneously during the regular use.